Japanese Patent Laid-open Publication No. HEI 9-195265 proposes a conventional self-propelled (self-propelled) soil modifying machine. 
This self-propelled soil modifying machine generally comprises a machine body having a traveling equipment, a raw soil hopper into which a soil to be modified i.e., a raw soil, is thrown, a belt conveyer for conveying the raw soil stocked in the raw soil hopper, a soil conditioner supply device for supplying a soil conditioner to the raw soil on the way of being conveyed by the soil conveyer, a mixer for mixing the raw soil with the soil conditioner so as to modify a quality of the raw soil and a modified soil conveyer for conveying the modified soil to discharge it out of the machine body. 
The soil conditioner supply device of the self-propelled soil modifying machine mentioned above comprises a soil conditioner  hopper into which the soil conditioner is thrown, a shooter disposed to a discharge port of the hopper, and a rotor having a plurality of feeder plates for feeding the soil conditioner stocked in the hopper to the discharge port, the rotor being provided to a bottom portion in the hopper. When the solid (powdery) soil conditioner is thrown into the hopper and the rotor is driven so as to be rotated, the soil conditioner is supplied through the shooter and dropped down on the raw soil conveyer. 
There may be used, as such soil conditioner, cement, cement-type solidifying agent, calcium lime, calcium hydroxide, lime-type solidifying agent, expandable beads and the like. 
Because of the above reason, the conventional self-propelled soil modifying machine of the type mentioned above is not suitable for a self-propelled soil modifying machine utilized for a CSG construction method. 
That is, in the CSG construction method, material prepared by mixing a soil at a construction site with cement is placed and spread over the construction site and then tamped for, for example, preparing or establishing a dam or the like, and in a case of less water containing ratio (water content) of a soil at the construction site, the water content is adjusted by adding water. However, such water content cannot be adjusted by the self-propelled soil modifying machine mentioned above, thus the conventional machine is not available. 
In the above, although the explanation has been made with reference to the CSG construction method as one example, in  another construction method, the self-propelled soil modifying machine of the conventional structure mentioned above is not proper for one for modifying soil by using liquid conditioner for solid conditioner as the soil conditioner. 